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      SUBROUTINE <a name="CGERU.1"></a><a href="cgeru.f.html#CGERU.1">CGERU</a>(M,N,ALPHA,X,INCX,Y,INCY,A,LDA)
<span class="comment">*</span><span class="comment">     .. Scalar Arguments ..
</span>      COMPLEX ALPHA
      INTEGER INCX,INCY,LDA,M,N
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Array Arguments ..
</span>      COMPLEX A(LDA,*),X(*),Y(*)
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Purpose
</span><span class="comment">*</span><span class="comment">  =======
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  <a name="CGERU.13"></a><a href="cgeru.f.html#CGERU.1">CGERU</a>  performs the rank 1 operation
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     A := alpha*x*y' + A,
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  where alpha is a scalar, x is an m element vector, y is an n element
</span><span class="comment">*</span><span class="comment">  vector and A is an m by n matrix.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Arguments
</span><span class="comment">*</span><span class="comment">  ==========
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  M      - INTEGER.
</span><span class="comment">*</span><span class="comment">           On entry, M specifies the number of rows of the matrix A.
</span><span class="comment">*</span><span class="comment">           M must be at least zero.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  N      - INTEGER.
</span><span class="comment">*</span><span class="comment">           On entry, N specifies the number of columns of the matrix A.
</span><span class="comment">*</span><span class="comment">           N must be at least zero.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  ALPHA  - COMPLEX         .
</span><span class="comment">*</span><span class="comment">           On entry, ALPHA specifies the scalar alpha.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  X      - COMPLEX          array of dimension at least
</span><span class="comment">*</span><span class="comment">           ( 1 + ( m - 1 )*abs( INCX ) ).
</span><span class="comment">*</span><span class="comment">           Before entry, the incremented array X must contain the m
</span><span class="comment">*</span><span class="comment">           element vector x.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  INCX   - INTEGER.
</span><span class="comment">*</span><span class="comment">           On entry, INCX specifies the increment for the elements of
</span><span class="comment">*</span><span class="comment">           X. INCX must not be zero.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Y      - COMPLEX          array of dimension at least
</span><span class="comment">*</span><span class="comment">           ( 1 + ( n - 1 )*abs( INCY ) ).
</span><span class="comment">*</span><span class="comment">           Before entry, the incremented array Y must contain the n
</span><span class="comment">*</span><span class="comment">           element vector y.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  INCY   - INTEGER.
</span><span class="comment">*</span><span class="comment">           On entry, INCY specifies the increment for the elements of
</span><span class="comment">*</span><span class="comment">           Y. INCY must not be zero.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  A      - COMPLEX          array of DIMENSION ( LDA, n ).
</span><span class="comment">*</span><span class="comment">           Before entry, the leading m by n part of the array A must
</span><span class="comment">*</span><span class="comment">           contain the matrix of coefficients. On exit, A is
</span><span class="comment">*</span><span class="comment">           overwritten by the updated matrix.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  LDA    - INTEGER.
</span><span class="comment">*</span><span class="comment">           On entry, LDA specifies the first dimension of A as declared
</span><span class="comment">*</span><span class="comment">           in the calling (sub) program. LDA must be at least
</span><span class="comment">*</span><span class="comment">           max( 1, m ).
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Level 2 Blas routine.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  -- Written on 22-October-1986.
</span><span class="comment">*</span><span class="comment">     Jack Dongarra, Argonne National Lab.
</span><span class="comment">*</span><span class="comment">     Jeremy Du Croz, Nag Central Office.
</span><span class="comment">*</span><span class="comment">     Sven Hammarling, Nag Central Office.
</span><span class="comment">*</span><span class="comment">     Richard Hanson, Sandia National Labs.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     .. Parameters ..
</span>      COMPLEX ZERO
      PARAMETER (ZERO= (0.0E+0,0.0E+0))
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Local Scalars ..
</span>      COMPLEX TEMP
      INTEGER I,INFO,IX,J,JY,KX
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. External Subroutines ..
</span>      EXTERNAL <a name="XERBLA.89"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Intrinsic Functions ..
</span>      INTRINSIC MAX
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Test the input parameters.
</span><span class="comment">*</span><span class="comment">
</span>      INFO = 0
      IF (M.LT.0) THEN
          INFO = 1
      ELSE IF (N.LT.0) THEN
          INFO = 2
      ELSE IF (INCX.EQ.0) THEN
          INFO = 5
      ELSE IF (INCY.EQ.0) THEN
          INFO = 7
      ELSE IF (LDA.LT.MAX(1,M)) THEN
          INFO = 9
      END IF
      IF (INFO.NE.0) THEN
          CALL <a name="XERBLA.110"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>(<span class="string">'<a name="CGERU.110"></a><a href="cgeru.f.html#CGERU.1">CGERU</a> '</span>,INFO)
          RETURN
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Quick return if possible.
</span><span class="comment">*</span><span class="comment">
</span>      IF ((M.EQ.0) .OR. (N.EQ.0) .OR. (ALPHA.EQ.ZERO)) RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Start the operations. In this version the elements of A are
</span><span class="comment">*</span><span class="comment">     accessed sequentially with one pass through A.
</span><span class="comment">*</span><span class="comment">
</span>      IF (INCY.GT.0) THEN
          JY = 1
      ELSE
          JY = 1 - (N-1)*INCY
      END IF
      IF (INCX.EQ.1) THEN
          DO 20 J = 1,N
              IF (Y(JY).NE.ZERO) THEN
                  TEMP = ALPHA*Y(JY)
                  DO 10 I = 1,M
                      A(I,J) = A(I,J) + X(I)*TEMP
   10             CONTINUE
              END IF
              JY = JY + INCY
   20     CONTINUE
      ELSE
          IF (INCX.GT.0) THEN
              KX = 1
          ELSE
              KX = 1 - (M-1)*INCX
          END IF
          DO 40 J = 1,N
              IF (Y(JY).NE.ZERO) THEN
                  TEMP = ALPHA*Y(JY)
                  IX = KX
                  DO 30 I = 1,M
                      A(I,J) = A(I,J) + X(IX)*TEMP
                      IX = IX + INCX
   30             CONTINUE
              END IF
              JY = JY + INCY
   40     CONTINUE
      END IF
<span class="comment">*</span><span class="comment">
</span>      RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     End of <a name="CGERU.157"></a><a href="cgeru.f.html#CGERU.1">CGERU</a> .
</span><span class="comment">*</span><span class="comment">
</span>      END

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